There is a sample measuring device (an optical measuring device) of this kind that makes an evaluation on physicality in a minute area of a sample or an analysis on a semiconductor element by the use of light (cathode luminescence) generated from the sample by irradiating electron beams on the sample.
The sample measuring device has an arrangement, as shown in the patent document 1, wherein an image is formed on an optical fiber or an entrance slit of a spectroscope arranged outside of an electron microscope by arranging a light collecting mirror part to cover a sample in order to collect cathode luminescence. Since the light collecting mirror part covers the sample, a path to pass the electron beams is arranged in order to irradiate the electron beams on the sample. The light collecting mirror part has to be positioned in order to set an axis of the electron beams inside the path since the electron beams from the electron microscope pass the path of the light collecting mirror part in conducting a measurement. Furthermore, a position on which the electron beams are irradiated has to be positioned within the focal point of the light collecting mirror part.
However, conventionally the axis of the electron beams has to be set inside the path and a position adjusting mechanism to move and adjust the light collecting mirror part is necessary in order to set the position on which the electron beams are irradiated within the focal point, thereby to make the measuring device complicated and enlarged. In addition, if the position adjusting mechanism is used, there is a problem that it becomes very troublesome to move and adjust the position adjusting mechanism.
Especially, in case of using a high-resolution scanning electron microscope, since an area on which the electron beams are irradiated is a minute area less than 10 nanometer, it is very difficult to adjust a position of the area to locate within a focal point of the light collecting mirror part. It is not easy to adjust the position in spite of skilled technique.
In addition, with the conventional arrangement, since the electron optical column part and the light collecting mirror part of the high-resolution scanning electron microscope are not fixed each other, a relative position of the electron optical column part and the light collecting mirror part might be changed due to vibration and it often happens that the position on which the electron beams are irradiated are displaced from the focal point of the light collecting mirror part.
Furthermore, since the light collecting mirror part as being a body separated from the electron optical column part is arranged between the electron optical column part (electron optical column body) of the electron microscope and the sample, an objective lens locating inside the electron optical column part obviously locates above the light collecting mirror part, thereby to lengthen a distance between a distal end at a sample side of the objective lens and the sample (hereinafter called just as a working distance (WD)). As a result of this, there is a problem that a spatial resolution of the sample measuring device is deteriorated. Patent document 1: Japan patent laid open number 2003-157789
The present claimed invention intends to solve all of the above-mentioned problems at once. Primary expected objects of this invention are to make it easy to adjust the position on which the energy beams are irradiated within the focal point of the light collecting mirror part, to prevent the position of the light collecting mirror part from being displaced due to vibration and to lessen the working distance (WD) to the minimum.